Prothena 10% owner William P Scully buys $1.2 million of shares
Open market purchase reported on Form 4, filed Oct 26, 2026.
Snapshot
William P Scully, a holder of more than 10% of the shares of Prothena (PRTA), bought 150,000 shares in open market purchases between Oct 22, 2026 and Oct 23, 2026, about $1.2 million at an average price of $8.15 a share, according to a Form 4 filed with the SEC on Oct 26, 2026.
- Independent Research
Market Data
| Company | 1D % | Price |
|---|---|---|
| ($PRTA) | ▲ +4.88% | 8.81 |
as of 16:00 ET · Realtime derived data
What We Know
The filing lists 2 open market purchase lines: • Oct 22, 2026: 100,000 shares at $8.19. • Oct 23, 2026: 50,000 shares at $8.07.
After the last purchase, the filing reports 1,187,000 shares held directly in that account.
Octans View
The purchases raised the holding reported in that account by about 14%, computed from the filed share counts. An open market purchase is made with the insider's own money at the market price, unlike option exercises or stock awards, which this brief excludes. The filing does not say why the insider bought.
Bear Case · Room for Disagreement
Limits. Insiders must report trades within two business days; this brief covers one filing and does not net it against sales by the same person or other insiders. Prices are as filed; where a line shows a weighted average, the filing's footnotes give the range.
Method and source. Octans Research reads the structured Form 4 filed with the SEC, keeps open market purchases (code P) only, and computes the total value and the average price from the filed share counts and prices. The filed price must sit within 25% of the closing price on the trade date. The text is generated by a fixed template; no model wrote it.
Chart
Sources
- [1]SEC EDGAR — Form 4 filed by William P Scully for Prothena, Oct 26, 2026
These are the sources this piece was drafted from. How we verify. Found an error? Tell us and we correct it in public.
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